1. Field of the Invention
The present invention relates to a torque transmission coupling for an automobile.
2. Description of the Related Art
Conventional torque transmission couplings include a torque transmission coupling incorporated with, for example, a transfer device as disclosed in Japanese Patent Application Laid-Open No. 2715340.
The transfer device has a torque transmission coupling. The torque transmission coupling has a clutch cage and a sleeve. A friction clutch is provided between the clutch cage and the sleeve. The friction clutch has outer plates and inner plates. The outer plates engage the clutch cage and the inner plates engage the sleeve.
A compression ring is disposed in opposition to the friction clutch. The compression ring engages a transfer case in the rotational direction, and is movable along the center axis of rotation. A support ring is disposed in opposition to the compression ring. A cam mechanism is provided between the support ring and the compression ring.
A gear engages the support ring. The gear is co-rotatably coupled to an shaft. The shaft is co-rotatably coupled to a driving shaft of a servomotor through an other gear and a pinion.
An output shaft for outputting torque to the sides of rear wheels is coupled to the clutch cage. The output shaft is co-rotatably coupled to an input shaft. The input shaft is transmitted a torque from an engine that receives a rotational input from the engine.
As such is the construction, the torque is transmitted to the input shaft from the engine. The torque transmitted to the input shaft is transferred, as it is, to the sides of the rear wheels through the output shaft. On the other hand, the torque is transferred to the sides of front wheels in response to the engagement of the friction clutch.
The engagement of the friction clutch is conducted by driving the servomotor. With the servomotor being driven, the pinion is rotated with the driving shaft of the servomotor, and the gear is rotated through the other gear and the shaft. With the rotation, the support ring is rotated within a range of 180 degrees, and rotates relative rotation with respect to the compression ring. The relative rotation causes the cam mechanism to function, and a thrust of the cam mechanism causes movement of the compression ring toward the friction clutch. This movement causes the engagement of the friction clutch.
However, according to the construction described above, a decelerating mechanism using the support ring, the gear, the other gear, and the pinion is large, so that it is hard to install the decelerating mechanism in a narrow spacing in the transfer device.